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Routines |
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Instructions from 28609 onwards can only be executed if, after moving down two character blocks, the next location to draw to is beneath the (two-character deep) floor, on the same character row as the "SPELLBOUND" text in the bottom window which shows either the copyright message if Magic Knight doesn't hold the Mirror, or Magic Knight's strength and inventory if he does.
Used by the routine at 28344.
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| 28561 | LD HL,(36488) | Load HL with display file address to draw character | ||||||
| 28564 | LD A,L | Clear all but least significant five bits (i.e. x-coordinate)... | ||||||
| 28565 | AND 31 | ... | ||||||
| 28567 | LD L,A | ... | ||||||
| 28568 | LD H,0 | ... | ||||||
| 28570 | PUSH HL | Store HL (x-coordinate to draw character) | ||||||
| 28571 | CALL 37719 | Move virtual text cursor to beginning of character row two rows below current position | ||||||
| 28574 | LD HL,(36488) | Load HL with display file address to draw character (as just updated) | ||||||
| 28577 | POP DE | Restore DE (new location to draw character, previously in HL) | ||||||
| 28578 | ADD HL,DE | Add x-coordinate as offset to updated location to draw character | ||||||
| 28579 | LD (36488),HL | Store the new location (now two characters below position upon entering this routine) | ||||||
| 28582 | LD HL,(23481) | Update current terrain interaction table cursor position onwards by 64 characters (i.e. down two rows)... | ||||||
| 28585 | LD BC,64 | ... | ||||||
| 28588 | ADD HL,BC | ... | ||||||
| 28589 | LD (23481),HL | ... | ||||||
| 28592 | LD HL,(36488) | Load HL with new display file address to draw character | ||||||
| 28595 | LD A,H | If memory location to draw character is not in the bottom third of the display... | ||||||
| 28596 | AND 248 | ... | ||||||
| 28598 | CP 80 | ... | ||||||
| 28600 | JR NZ,28645 | ...then return | ||||||
| 28602 | LD A,L | If memory location to draw character is not in the fifth character row (any of the 8 pixel rows)... | ||||||
| 28603 | AND 224 | ...(which is the row two rows beneath the floor level, in line with "SPELLBOUND" text in bottom window)... | ||||||
| 28605 | CP 128 | ... | ||||||
| 28607 | JR NZ,28645 | ...then return | ||||||
| 28609 | LD A,64 | Load 64 into MSB of display file address to print character, wrapping from bottom of display back up to top... | ||||||
| 28611 | LD (36489),A | ... | ||||||
| 28614 | LD A,(36488) | Increase LSB by two characters (moving right by two characters upon bottom-to-top wrap)... | ||||||
| 28617 | INC A | ... | ||||||
| 28618 | INC A | ... | ||||||
| 28619 | AND 31 | Cap value to maximum of 31 to ensure that new position is in top character row of display (i.e. y-coordinate = 0)... | ||||||
| 28621 | LD (36488),A | ...and store | ||||||
| 28624 | LD BC,24539 | Point BC at terrain interaction table | ||||||
| 28627 | XOR A | Set A to zero (and clear carry flag) | ||||||
| 28628 | LD HL,(23481) | Load HL with terrain interaction table cursor | ||||||
| 28631 | SBC HL,BC | Load HL with position of terrain interaction table cursor relative (i.e. offset) to beginning of the table | ||||||
| 28633 | LD A,L | Advance cursor x-coordinate offset by two character blocks... | ||||||
| 28634 | INC A | ... | ||||||
| 28635 | INC A | ... | ||||||
| 28636 | AND 31 | ...and cap value to maximum of 31 to ensure that new position is in top character row of display (i.e. y-coordinate = 0)... | ||||||
| 28638 | LD L,A | Place new x-coordinate in HL along with y-coordinate of zero... | ||||||
| 28639 | LD H,0 | ... | ||||||
| 28641 | ADD HL,BC | Add this new offset to start of terrain interaction data | ||||||
| 28642 | LD (23481),HL | Store the updated terrain interaction table cursor | ||||||
| 28645 | EXX | Switch registers | ||||||
| 28646 | RET | Return | ||||||
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